Antimicrobial isocyanides

ABSTRACT

Isocyanides of the formula WHEREIN Z represents oxygen or sulfur; R represents hydrogen, halogen, lower alkyl, lower alkoxy, phenyl-lower alkylene, phenyl-lower alkyloxy, trifluoromethyl, cyano, or dimethylaminosulfonyl; R1 and R2 represent hydrogen, halogen, lower alkyl, lower alkoxy, phenyl-lower alkylene, phenyl-lower alkyloxy, trifluoromethyl, cyano, dimethylaminosulfonyl, or isocyanido; and n is 1 or 2, provided that at least one of R1 and R2 is hydrogen, and that when R is other than hydrogen, R and the isocyanido group are positioned, respectively, either ortho and para or para and ortho with respect to Z. These compounds possess utility as antibacterial and parasiticidal agents. They have also demonstrated activity as CNS depressants.

United States Patent n 1 Yale [ 51 Jan.30,1973

1541 ANTIMICROBIAL ISOCYANIDES Harry L. Yale, New Brunswick, NJ.

[73] Assignee: E. R. Squibb & Sons, Inc., New

York,N.Y.

[63] Continuation-impart of Ser. No. 758,115, Sept. 6,

1968, abandoned.

[75] Inventor:

[5 6] References Cited UNITED STATES PATENTS 10/1966 Ugi et al. 260/465 12/1968 Fet'zer et al.. v

1/1969 Ugi et a1. ..260/465 Primary Examiner-Lewis Gotts Assistant Examiner-C. F. Warren Attorney-Lawrence S. Levinson, Merle .1. Smith, Donald J. Perrella and Burton Rodney 571 ABSTRACT lsocyanides of the formula wherein Z represents oxygen or sulfur; R represents hydrogen, halogen, lower alkyl, lower alkoxy, phenyllower alkylene, phenyl-lower alkyloxy, trifluoromethyl, cyano, or dimethylaminosulfonyl; R' and 1?. represent hydrogen, halogen, lower alkyl, lower alkoxy, phenyl-lower alkylene, phenyl-lower alkyloxy, trifluoromethyl, cyano, dimethylaminosulfonyl, or isocyanido; and n is 1 or 2, provided that'at least one of R and R is hydrogen, and that when R is other than hydrogen, R and the isocyanido group are positioned, respectively, either ortho and para or para and ortho with respect to Z, These compounds possess utility as antibacterial and parasiticidal agents. They have also demonstrated activity as CNS depressants.

4 Claims, No Drawings ANTIMICROBIAL ISOCYANIDES This application is a continuation-in-part of application Ser. No. 758,115 filed Sept. 6, 1968, now abandoned.

This invention relates to novel isocyanides of the formula wherein Z represents oxygen or sulfur; R represents lower alkylene, phenyl-lower alkyloxy, trifluoromethyl, cyano, or dimethylaminosulfonyl; R and R each represents hydrogen, halogen, lower alkyl, lower alkoxy, phenyl-lower alkylene, phenyl-lower alkyloxy, trifluoromethyl, cyano, dimethylaminosulfonyl, or isocyanido; and n is l or 2, provided that at least one of R and R is hydrogen and that when R is other than hydrogen, R and the isocyanido group are positioned, respectively, either ortho and para or para and ortho with respect to Z.

The term halogen encompasses chlorine, bromine, fluorine and iodinev Chlorine and bromine are preferred.

The term lower alkyl as employed herein includes both straight and branched chain radicals of up to eight carbon atoms, for instance, methyl, ethyl, propyl, isopropyl, butyl, t-butyl, isobutyl, pentyl, hexyl, isohexyl heptyl, 4,4-dimethylpentyl, octyl, 2,2,4-trimethylpentyl and the like.

The term lower alkoxy includes straight and branched chain radicals which correspond to the above In the case of the nitrophenyl ether (II), the nitro 7 group is then reduced to an amine as by treatment with a reducing agent such as nascient hydrogen, which may be formed in situ by the action of an electropositive metal, such as iron, on an acid, such as hydrochloric acid, thereby forming the corresponding 2-(benzyloxy)aniline derivative. Alternatively, the nitro group may be reduced by catalytic hydrogenation, as for instance with a palladium catalyst in the presence of an alcohol, such as ethanol or isopropanol.

The aniline derivative is then treated with formic acid, whereby the corresponding formanilide derivative (IV or VII) is produced.

The formanilide derivative may then be reacted with a mixture of 1 equivalent each of phosgene and triethylamine in a solvent such as methylene chloride to I produce the desired isocyanides (V and VIII) which are the final products of this invention.

Alternatively, the formanilide derivative may be reacted witha mixture of one equivalent each of pyridineand either benzenesulfonyl chloride or ptoluenesulfonyl chloride, again in a solvent such as methylene chloride. I

It will be understood, of course, that in those cases fect floors, walks, tables and the like. They are also useful as laboratory reagents to prevent overgrowth of the above when attempting to demonstrate the presence of other organisms, such as Klebsiella species in cultures. These compounds are also useful as central nervous system depressants when employed in animal species. As such they may be administered to animals, such as cats, dogs, mice, horses, cattle, and the like, in the treatment of hyperirritability in oral dosage forms, such as tablets or capsules, in a dosage range of about 10 to 500 mg. per day. They may, addition, be administered in a suitable parenteral formulation, such as an oil suspension if so desired.

The following examples illustrate the invention. All temperatures are in degrees Centigrade.

EXAMPLE I o-[ (o-Bromobenzyl)thio]phenyl isocyanide A. Preparation of o-[(o-bromobenzyl)thio]aniline hydrochloride To a stirred solution of 119.5 g. of o-bromobenzyl bromide and 62.5 g. of o-aminobenzenethiol in 400 ml. of 95 percent ethanol, thoroughly purged with nitrogen, is added dropwise a solution of 39.6 g. of 85 percent potassium hydroxide in 200 ml. of water and the reaction mixture subsequently refluxed for two hours. The mixture s then concentrated to dryness. The residue is dissolved in one liter of ether.'This ether solution is dried and treated with 2.5 N ethereal hydrogen chloride to give o-[(o-bromobenzyl)thiolaniline hydrochloride. 4

'B. Preparation of o-[(o,-bromobenzyl)thio1forman ilide To 11.47 g. of. o-[(o-bromobenzyl)thiolaniline hydrochloride is added 5.0 g. of dry sodium formate and 67 ml. of 98-100 percent formic acid, and the mixture refluxed for three hours and then concentrated to dryness on the rotary evaporator. The residue is triturated with a mixture of ml. of water and 50 ml. of ether until granulation occurs. The solid is filtered to give 9.6 g. of material,'m.p. l10l 12. Recrystallization from heptane gives o-[(o-bromobenzyl)thiolformanilide, m.p. 11'21l4.

C. Preparation of o-[(o-bromobenzyl)thiolphenyl isocyanide To 23.0 g. of crude formamido derivative, 18.3 g. of triethylamine, and 185 ml. of reagent grade methylene chloride is added dropwise in 1.5 hours 57 ml. of a 13.9 percent solution of phosgene in toluene, maintaining the reaction temperature at 2 to 4. Subsequently, the temperature is allowed to rise to 10 during 2 hours, then allowed to rise to 20 and'l85 ml. of an ice-water mixture is added. The organic layer is separated, dried, and concentrated on the rotary evaporator. The semisolid residue is dissolved in 250 ml. of benzene and poured on a column of 190 g. of Harshaw activated alumina, chromatographic grade, prepared in benzene. The elution is effected with 20 percent chloroformpercent hexane. The following summarizes the chromatographic results:

Cut I, 250 ml. benzene solvent residue Cut II, 250 ml. mostly benzene 11.0 g. solid residue Cut III, 250 ml. Cl-ICl;,-he xane 2.30 g. solid residue 1 Cut IV, 250 ml. CHCh-hexane 1.70 g. solid residue I Cut V, 250 ml. Cl-lCl -,-hexane' 0.90 g. semi.- solid residue Cut VI, 250 ml. Cl-ICl -hexane trace semisolid residue 1 Cut VII, 500 ml. CI-ICl -hexane trace oil. Cuts II, III, IV, and V are triturated with 140 ml. of boiling pentane, and the hot pentane solution decanted. The pentane insoluble material is recrystallizedfrom 340 ml. of hexane and dried at 56 to give 7.45 g. of large pale yellow prisms, m.p. 88-90.

EXAMPLEZ.

0.06 g. solid o-[ (o-Bromobenzyl)oxy]phenyl isocyanide A. Preparation of o-[(o-bromobenzyl)oxylnitrobe nzene To a stirred solution of 1 19.5 g. of o-bromobenzyl bromide and 83.6 g. of o-nitrophenol in 400 ml. of'95 percent ethyl alcohol is added dropwise a solution of 39.6 g. of percent potassium hydroxide in 200 ml. of

water and the reaction mixture subsequently refluxed for two hours. After cooling, the product separates and is filtered, washed well with water, and air dried to give about 149.6 g. of o-[(o-bromobenzyl)oxy]nitrobe nzene, m.p. about 8283. Upon recrystallization from percent ethyl alcohol, the product melts at 82.583

A mixture of 78.8 g. of o-[(o-bromobenzyl)oxy]- aniline hydrochloride, 34.0 g. of dry sodium formate, and 460 ml. of 98-100 percent formic acid is stirred and heated under reflux for 3 hours, cooled somewhat, and poured into 1 l. of ice-water. The solid which separates is filtered and washed with water to give 61.4 g. of o-[(o-bromobenzy1)oxy]formanilide, m.p. ll3114.

D. Preparation of o-[(o-bromobenzyl)oxy]phenyl isocyanide To 27.2 g. of the formamide derivative, at to is added dropwise 64 ml. of a 13.9 percent solution of phosgene in toluene (equivalent to 8.8 g.). The reaction is exothermic and 1.5 hours are required for the addition. The mixture is allowed to warm to in three hours and to in 0.25 hours, at which time 222 ml. of ice-water is added. To organic layer is separated, dried, and concentrated to dryness on the Rinco. The residual brown oil crystallizes spontaneously; it weighes 26.4 g., m. 5873. Thin layer chromatography on silica gel gives a blue fluorescing spot, R, 0.5 (5 percent CHCl --95 percent petroleum), R, 0.69 (10 percent CHC1 -90 percent petroleum ether). The formamido compound does not move in these systems (R =0.0). The entire crude product is extracted with 1350 ml. of boiling hexane, the hexane filtrate is refluxed 0.25 hour with 1 g. of Darco and 0.5 g. Hyflo and filtered. The filtrate deposites a crystalline product (Solid A) which is filtered and dried to give 10.8 g. of yellow solid, m.p. 73-83.

In the infrared this material shows strong absorption at 2125 cm (N=C) and 1708 cm- C=0). That the latter absorption is due to an impurity is demonstrated by micro sublimation: 0.2 g. is heated at l70/0.05 mm. to give 0.13 g. of a colorless solid, m.p. 78-80 which shows strong absorption at 2125 cm but no absorption at'1708 cm". In the process, however, the residue from the sublimation is converted to a black tar. Since it is desirable to identify the impurity in the isonitrile, column chromatography is employed.

The hexane filtrate from Solid A is concentrated to 300 ml. and poured on a column of Harshaw activated alumina prepared in hexane. Elution with 80 percent hexane20 percent chloroform (240 ml. for each elution) yields the following:

1.4.09 g., m.p. 80-82 2.1.78 g., m.p.79-81 3. 0.75 g., m.p. 8084.

At this point there remains a yellow band on the column, and this is eluted with 240 ml. of chloroform. The chloroform eluate yields 1.35 g. of residue (4), m. 7187.

(l), (2), and (3) are recrystallized from 75 ml. of hexane to give 6.53 g. of colorless crystals, m. 84.0- 85.5, showing only strong absorption at 2125 cm and no absorption at 1708 cm.

Solid A (10.8 g.) is dissolved in 600 ml. of hexane, chromatographed on 150 g. of Harshaw activated alu mina, and eluted as above, except that each elution is 480 ml. of 80 percent hexane-20 percent chloroform. The following are obtained:

1) 0.32 g., no m.p. taken 2) 4.23 g., m.p. 79-81 3) 0.86 g., m.p. 79-8 1 4) 0.55 g., no m.p. taken.

480ml. chloroform eluate yielded 3.6 g. of material (5).

From the hexane recrystallization of (1), (2), (3), and (4) there is obtained 5.67 g. of material, m.p. and mixture m.p. with the product above, 84.0-85.5.

The 1.35 g. of residue from the chloroform elution of the first chromatogram was recrystallized from 30 ml. of hexane to give 0.97 g. of additional isocyanide, m.p. and mixture m.p., 84.0-85.5. The total yield of product, 2-[(o-bromobenzyl)oxy]phenyl iso-cyanide, is 13.13 g.

The 3.6 g. of residue from the chloroform elution of the second chromatogram is recrystallized from 65 m1. of Skellysolve E to give 1.0 g of the starting formamido compound, identified by m.p., mixture m.p., and infrared spectrum. The presence of this material accounts for the absorption at 1708 cm".

EXAMPLE 3 2-o-Methylphenethyl Bromide A. To 24.3 g. of magnesium turning in l 1. of anhydrous ether is added a crystal of iodine and 25 ml. of a solution of 171 g. of o-bromotoluene. The reaction is initiated by slight heating, and the remainder of the obromotoluene solution is added with stirring at a rate to maintain a moderate reflux. Subsequently, the mixture is stirred and refluxed for 1 hour, cooled with wet ice, and a stream of ethylene oxide gas introduced into the rapidly agitated o-tolylmagnesium bromide. The mixture is tested periodically and when it gives a negative color test with Michlers ketone-iodine, the introduction of ethylene oxide is terminated. The mixture is made slightly acid with 10 percent aqueous hydrochloric acid and the ether layer is separated, washed with saturated aqueous sodium chloride solution, dried, concentrated, and the residue distilled to give 2-0- methylphenethyl alcohol. B) To the product from A), 68 g., in 250 ml. of alcohol free chloroform is added dropwise 104 g. of thionyl bromide. Subsequently, the mixture is stirred and refluxed for 1 hour, concentrated, and the residue distilled to give 2-0- methylphenethyl bromide.

EXAMPLE 4 p-Bromomethylbenzonitrile bromide and distilled to give p-bromomethylbenzonitrile.

EXAMPLES p-Br0momethyl-a,a,a-trifluorotoluene To g. of a,a,a-trifluoro-p-xylene and 1.0 g. of benzoyl peroxide at is added dropwise g. of

bromine while the mixture is irradiated by means of an ultraviolet lamp. The addition requires 1 hour. Sub- EXAMPLE 6 o( Benzyloxy)benzyl Bromide A. To 152 g. of methyl salicylate in 500 ml. of absolute methanol is added in portions a total of 54 g. of dry sodium methoxide and the mixture stirred for 1 hour. To the mixture is then added dropwise 171 g. of benzyl bromide and the whole, subsequently, refluxed for 1 hour. The methanol is removed on the rotary evaporator, and the residue distributed between I l. of ether and 500 ml. of water. The ether layer is separated, washed, dried and concentrated to give methyl o-benzyloxybenzoate:

B. To 121 g. of the product from A) in 500 ml. of anhydrous ether is added dropwise a solution of 19 g. of lithium aluminum hydride in 250 ml. of anhydrous ether. Subsequently, the mixture is stirred and refluxed for 1 hour and worked up to give o-benzyloxybenzyl alcohol.

C. Employing the procedure of Example 3 B) but, substituting 107 g. of the product from B) for the product in that example, there is obtained o-benzyloxybenzyl bromide.

EXAMPLE 7 2-p-Methoxyphenethyl Bromide A. Following the procedure of Example 3 A) but substituting 187 g. of p-bromoanisole for the obromotoluene, there is obtained p-methoxyphenethyl alcohol.

B. By substituting 76 g. of the product from A) for the 2-o-methylphenethyl alcohol in Example 3 B), there is obtained 2-p-methoxyphenethyl bromide.

EXAMPLE 8 N,N-Dimethyl-p-bromomethylbenzenesulfonamide By substituting g. of N,N-dimethyl-p-toluenesulfonamide for the p-tolunitrile in Example 4 B), there is obtained N,N-dimethyl-p-bromomethylbenzene-sulfonamide.

Example 9 o-(Benzyl)benzyl Bromide A. A solution of 42.4 g. of diphenylmethane-Z-carboxylic acid, 400 ml. of methanol, and 20 ml. of concentrated sulfuric acid is refluxed for 4 hours and concentrated on the rotary evaporator. The residue is cooled, and treated with 500 ml. of ether and 300 g. of ice. The mixture is shaken thoroughly and the ether ayer is separated, washed with water, 2 percent aqueous sodium hydroxide, saturated sodium chloride, dried, concentrated and the residue distilled to give methyldiphenylmethane-Z-carboxylate.

B. The product from A), 45.2 g., in 200 ml. of dry ether is reduced with 7.6 g. of lithium aluminum hydride as in Example 6 B) to give o-(benzyl)benzyl alcohol.

C. The product from B), 19.8 g., in 200 ml. of alcohol free chloroform is reacted with 20.4 g. of thionyl bromide as in Example 3 B) to give o-(benzyl)benzyl bromide.

Following the procedure of Example 1 or 2, whichever is pertinent, but employing as starting materials the aminothiophenol or nitrophenol shown in Column A and the benzyl or phenethy] halide shown in Column B, the product shown in Column Cis obtained.

S H ClCH2 NH2 Cl O-(CHz):

SCH2

What is claimed is: 1. An isocyanide of the formula wherein Z is selected from the group consisting of oxygen and sulfur; R is selected from the group consisting of hydrogen, halogen, alkyl containing one to eight carbons, alkoxy containing one to eight carbons, phenyllower alkylene containing one to four carbons in the alkylene group, phenyllower alkyleneoxy l to 4 carbons in the alkyleneoxy group, trifluoromethyl, cyano, and dimethylaminosulfonyl; R and R are each selected from the group consisting of hydrogen, halogen, alkyl containing one to eight carbons, alkoxy containing one to eight carbons, phenyl-lower alkylene containing one to four carbons in the alkylene group, phenyl-lower alkyleneoxy containing one to four carbons in the alkyleneoxy group, trifluoromethyl, cyano, dimethylaminosulfonyl, and isocyanido; and n is.1 or 2,

provided that at least one of R and R is hydrogen, and

that when R is other than hydrogen, R and the isocyanido group and positioned, respectively, either ortho and para or para and ortho with respect to Z, and where R is halogen, R and R can be a halogen selected from the group consisting of. chlorine and bromine.

2. A compound according to claim 1 wherein R is selected from the group consisting of hydrogen and I T 686a LiLRTiFICATE 9F COBRECTIDN Date; January 3 1973 Inventor(s) Harry Louis Yale It is certified that error appears in the above-identifi d patent and that said Letters Patent are hereby corrected as shown below:

Column 1, formula I under column A, that portion of the formula which reads:

Q R should be: R :Q

' NO 0 Y H I 2 Column 13, line 60, Claim after "alkyleneoxy" ,insert containing Signed and sealed this 10th day of July 1973'.

(SEAL) Attest:

EDWARD M.FLETCHER,JR." Rene .Tegtmeyer Attesting Officer Acting COIHHllSSlOIIGT of Patents 

1. An isocyanide of the formula wherein Z is selected from the group consisting of oxygen and sulfur; R is selected from the group consisting of hydrogen, halogen, alkyl containing one to eight carbons, alkoxy containing one to eight carbons, phenyl-lower alkylene containing one to four carbons in the alkylene group, phenyl- lower alkyleneoxy 1 to 4 carbons in the alkyleneoxy group, trifluoromethyl, cyano, and dimethylaminosulfonyl; R1 and R2 are each selected from the group consisting of hydrogen, halogen, alkyl containing one to eight carbons, alkoxy containing one to eight carbons, phenyl-lower alkylene containing one to four carbons in the alkylene group, phenyl-lower alkyleneoxy containing one to four carbons in the alkyleneoxy group, trifluoromethyl, cyano, dimethylaminosulfonyl, and isocyanido; and n is 1 or 2, provided that at least one of R1 and R2 is hydrogen, and that when R is other than hydrogen, R and the isocyanido group and positioned, respectively, either ortho and para or para and ortho with respect to Z, and where R is halogen, R1 and R2 can be a halogen selected from the group consisting of chlorine and bromine.
 2. A compound according to claim 1 wherein R is selected from the group consisting of hydrogen and halogen, R1 is halogen, and n is
 1. 3. A compound in accordance with claim 2 wherein R is hydrogen, R1 is bromine, n is 1, Z is sulfur, and the isocyanido group is positioned ortho to the sulfur. 